Milky spores vs Nematodes.

Since you’ve guys never failed me yet i have a question. So i just recently planted a Japanese flowering tree and now am having the Japanese beetle problem. I kind of had them prior to that. I did a grub treatment about 2 months ago. Ive been reading about how using Nematodes or Milky spores helps reduce their population. With that being said which is better? How and when to apply them? (im assuming its to late this year) What brand is better? Thank you in advance.